Injection type carburetor



Oct. 21, 1958 T. A. MORRIS INJECTION TYPE: CARBURETOP.

Filed Feb. 27, 1951 United States Patent INJECTION TYPE CARBURETOR Thomas A. Morris, Detroit, Mich.

Application February 27, 1951, Serial No. 212,871 s claims. (C1. asl-2s) 'The invention relates to a carburetor for feeding fuel to multicylinder internal combustion engines and is an improvement in carburetors of the general type shown in my Patent No. 2,428,377 issued October 7, 1947.

According to my present invention, a construction is provided for feeding liquid fuel from a single metering means through conduits connected to a plurality of separate inlet manifolds, each leading to the individual cylinders of the engine. Each inlet manifold is provided with a separate throttle valve, all of which are mechanically connected together so as to be simultaneously operated. The liquid fuel conduits communicate with the respective manifolds on the engine side of the throttle valves. The single metering means-is controlled by a differential pressure obtained from the opposite sides of the throttle valve in one or more of the inlet manifolds, andV the actuation of the metering means is caused by suction motor means responsive to said differential pressure. By feeding the liquid fuel directly into the manifoldsleading to the individual cylinders `instead of into a common manifold having branched connections, the distributive problems are overcome and surging due to the cross ow from the overlapping induction strokes is eliminated.

The invention is hereinafter fully described by reference to the accompanying drawings, wherein:

Figure l is a vertical section througha carburetor embodying my invention with some of the operating connections being diagrammatically shown; and

Figure 2 is an enlarged vertical section through the main Venturi of one of the inlet manifolds of Figure 1.

In Figure l there is shown a manifold construction for a vsix cylinder engine with separate downdraft inlet manifolds, 11a, 11b, 11C, 11d, 11e and 11f for each of tthe cylinders. Each of the inlet manifolds has its upper end 12 adapted to be connected to the air supply and the lower end 13 adapted to be connected to an individual cylinder of an internal combustion engine (not shown). Each manifold has a butterfly throttle valve 14, and a main Venturi member 15 on the inner side of said throttle valve, that is, between the throttle valve and the engine cylinder. The throttle valves 14 are mechanically connected together so as to be simultaneously operated and, as diagrammatically shown, this is accomplished by the common shaft 92. Each manifold also has a second vVenturi member 16 on the outer side of said throttle valve, that is, between said throttle valve and the air supply.` The main Venturi member 15 serves to admit liquid fuel vinto the air stream to thereby form the fuel mixture and for this purpose the Venturi member 15 is preferably provided with a circumferential series of small radial fuel ports 16a arranged at points adjacent the plane of greatyest restriction in area. These ports 16a are supplied with liquid fuel from the fuel feed conduits 93, all of which `are connected to the conduit 94` leading from the metering device 19 which in turn is connected by a conduit 17 to a pressure regulator 18.`

The metering device 19 has slidably arranged therein :a double ended needle valve 20 within the chamber 22.

2,857,145l Patented Oct. 21, 1958 ICC supply port 24 which leads to the conduit 94. The needle Y valve 20 has a shut-off face 26 adapted to bear against a seat 27 surrounding the port 24 and has a tapered metering valve portion 28 cooperating with the metering port 23 to regulate the amount of ow of the fuel. The needle valve 20 has an actuating stem 29 which is connected to the controlling mechanism.

lThe controlling mechanism for the liquid fuel metering device is responsive primarily to the suction produced by the two Venturi members 15 and 16 on opposite sides of the throttle valve 14 in one or more of the inlet manifolds. The controlling mechanism is preferably operated by a suction motor 30 which consists of a. housing 31 containing a flexible diaphragm 32 dividing the housing into an upper chamber 33 responsive to the suction of the main or inner Venturi 15 by means of the connecting conduit 34 and a lower chamber 35 responsive to the suction of the second or outer Venturi 16 bymeans of the connecting conduit 36. The conduit 34 is connected to the annular passage 37 which `in turn is connected to the throat of the main Venturi member 15 by a series of radial suction ports 38 intermediate the radial fuel ports 16a. The other end of the connecting conduit 34 communicates with a valve chamber 39 which is connected to the chamber 33 by a small passageway 40 and is alsoconnected to the chamber 33 by the larger passageway 41 which, however, is normally closed by the check valvel 42 held to its seat by a spring 43. In order to prevent any blocking of the small passageway 40, a pin 44 extends through this passageway and has an enlarged head 45 resting by gravity on the flanges 46 of the diaphragm 32. The connecting conduit 36 communicates with an annular passageway 47 which in turn leads to the throat of the second Venturi member 16 by a series of radial suction ports 48. The other end of the conduit 36 communicates with the chamber 35 below the diaphragm 32. This chamber is formed by the conical lower wall 49 having a bleed opening 50 for introducing atmosphereic air at a predetermined rate. The bleed hole 50 is kept clean from dirt accumulation by a spring wire 50a connected to the `diaphragm 32 to move therewith and continually probe through the hole. A member 51 secured to the diaphragm extends through the conical wall 49. A thermostatic coil spring 52 is arranged within and connected to the annular wall 53 depending from the housing 31, which Wall 53 is arranged in heat conductive relation to the engine (not shown). A rod 54 threadedly secured to the member 51 and passing through a bearing 55 is attached to the inner end of the thermostatic spring 52 in such a way that any change in temperature causes a rotation of the rod 54 to correspondingly increase or decrease the length between the diaphragm 32 and the rod 54. Another rod 56 has a swivel connection 57 with the rod 54 and is connected by a link 58 to a bell crank lever 59, the other arm 60 of which is connected to the stem 29 of the needle valve 20.

In order to permit the needle valve 20 to be responsive to changes in barometric pressure, I have provided the following construction. 61 is a metallic bellows secured to a stationary support such as the bracket 62 and the opposite end of the bellows is connected to a rack bar 63 which is in mesh with a pinion 64 on a shaft 65. On this same shaft is a cam 66 which engages a roller bearing 67 on one end of a lever 68, the opposite end of which engages the cap 69 for a conical spring 70 seated upon the sleeve 71 on the rod 56. This construction is to some extent a diagrammatic representation of a con-- nection between the bellows 61 and the rod 56 to apply a variable force thereto cooperating with the force produced by the movement of the diaphragm 32. By suit-V 3 ably fashioning the earn. 65.- this force produced. byV the bellows 61 will'always be in the correct ratio to the change in the density ofthe air.

In order to insure a complete closure of the needle valve 2Q against1 the seatx 2f7', there isprrovidedmeans for holding the needle vfalve` to'its seaty when the` engine is. not. in oper-ation This. ineens eonihrises. a. spring 7.2 Whieh hears.. against an. artn 7.3' trent the. hell. eranlsnlever. 59 and aetuating said. lever. in a direetion. to.; seat. the. needle valve. 2.0L" The. spring 7.2.;- is. sleeved'. upon. o tod'. 74 which forms the core rnernberY ofja s olenoid'ZS. One ofthe springs is.- seated on the casingojfjthe solenoid and its opposite endA engages a collar-7.6 fwhich bears againstV a shoulder on. a slotted. headWs. aninjttzonthearm 'la engages. the slot; in said head: 7.1an'd the a. .angentent is.. such. that when. the solenoidzlSiis de ene operatingthrough.. the. Collar 76 ein aetuatesy the. ann. 73' to hold. the valve. 29. to.. itsx s.e.a..t.-l I fs on the other. hand, the. solenoid; 7.51 is., energized, this Will. draw downward; the rod, drelieving pressure. against the Pin. 78 so as to permitthe bell cranlg lever 59 to be actuated solely by its. other. eonneetiuns The soil. of. the. solenoid 75' may.l he. eonneeted. to the. eleetrio generator of. the. engine so. that it will always. he. energized. when. the engine isonerating The. discharge. of. fuel. into. the. mixture eonduits. 11u. to 11i is. not dependent. solely, upon the suetion. of: the man venturi 1.5. but is.. unser a; positive. haas; It is essential that. this. head. should.. remain. Constant. and for this purpose thei followingv cpnstruction is provided. 80 is. a easing Containing a.. flexible diaphragrn. 8.1. whieh. divides. the.. interior. int-o. two chambers. Siano 83- 8.4 is, a tube. oonneeting with and passing. through the. eentet of. the diaphragm. and slidably, engaging. at. it'supper. end. a pin 85. 'A Port 8.8.. eonneofs the'. elharhher 82./with-the. interior of. the.. tube andthe lower end. ot thetuhe. Whieh. is. inthe ohatnher. 8.3. 1s. Inoxedhy the. llexing of. the diaphragm in. relation. to a metering' rnernher. 8.6. which restlriets. the open atea.. as the. diaphragm. moves. downward. and. enlarges said. area as. it. moves upward. A spring 87. resiliently lifts the diaphragm. The fuel conduit 1,7 is. connected to, the chamber 8 3 andar fuel supply Conduit 89. is eonneeted. to the eharnher Thus. the pressure of the liquid, fuel in the chamber 8 2 is balanced against the. spring 8.7 which. lifts the. diaphragrn- Should' the pressure. increase in. the chamber. 8.2., this., b y depressing the dianhragm. and movingA the tube 84 towards the metering device 8.6, restricts the opening for the passage `of fuel intox the chamber 83, On the other hand,yif the pressure in the chamber 82, becomes less, the cliaphragm will be raised and, the discharge area around the metering device 8d, enlarged, Therefore when the engine is. in operation, the, pressure within thel chamber 83 is maintainedsubstantially constant regardless of' fluctuations` in pressurey of the liquids in the chamber 82.

In the operation of the devices. fuel, for the pressure regulator 18 is discharged through the feed conduit 1,7 into the metering device 19 which isy controlled by the conjoint action of the suction. r n otor3 0, the therrnostatic coil 52 and the bellows. 61 responsivetochanges in barometric pressure, The suctiont motor 30- is directly responsive to the manifold pressure by reason of the. con. duit 34 connected into. the throat of the main, Venturi 15, but it is also responsive to variations. inl velocityy ofA the gases passing through the, manifold by reason of the conduit 36 connected into. the throat of the auxiliary Venturi 16. on the outer side of the throttle valve.k By reason of this latter connection to the Venturi 16, an increase in the velocity of the air passing through the.y manifold will increase the discharge of fuel, while a decrease in the velocity of air will, correspondingly de.- crease the discharge of fuel, through saidl ports.y However, the principal regulation. of the metering device,r is obtained. by reason of the Change in v-aeuurn. Protlueed.. at the throat of; the main. Venturi 1.5. in aeeordanee. with..

4., the. manifold pressure. It will. also beohserved. that the negative pressures derived from the two Venturis andl 16I are applied on opposite sides of the diaphragm 32 of the suction motor andi therefore it is the resultant of the two forces on opposite sides of the diaphragm derives its actuating',forceN4 from; the, connections to two of the sin` inletY n 1alnifoldlsv butY it controls the metering of the fuel to all' six of" the manifolds from the single metering device 193x It; will be. understood, however, that the conduits 34 and 36 may be connected to but a single inlet manifold -or to all or any part of the same but in every case there is only one metering device which supplies the liquid fuel to all of the, inlet manifolds on 'the engine side o ff` the throttle valves in each manifold;

The primary function` of thel shut-offl face 26 of the needle valve 20 is tocompletcly close the connection between thev fuel* supply conduit 1f7'- and the discharge ports 16u whenthe engine is notl in operation. A further function of this element* is to form an additional metering means which is effective under certain conditions in"operation. Thus when the, engine is operating. under heavy load; the throttle may be fairly wide open butthe speed ofI the engine and consequent velocity 'ofi the gaseousF mixture through the inletuisl relatively-low.v Under such conditions there isl a tendency to dischargeA more fuel than requiredfor-thequantity of air. Howeverfthe shut-offgface ,26 of the needle valve 20 is tapered; to engage the cooperating seat 27- and this operates asa meteringv device-to restrictthe fuell discharge asthe, suction is loweredl until finally, the-valve closes to cut* off all fuel:

What; Ij claim as myfinventon is:-

1. In a carburetor for internalv combustion engines,the combination, of a plurality of inlet'conduits leading to dif-v ferentA cylinders of thev engine, each conduit having respectively a throttle valve, a Venturi on the innerhside of t said throttle valve, a Venturionthelouter side of said throttle valve andf aw fuel injection port in said inner Venturi, a single metering means for the fuel supply,- fuel connections between saidsinglemetering means and-each of said fuel injection ports'a suction motor having. a housing,y a flexibleA diaphragm in saidhousing forming suctionl'chambers on opposite sides thereof, said diaphragm being operatively connected to said metering means', a suction conduit-from oneorfmore of saidinnen Venturis connected tothe chamber of said motor onroney side of said liexible ,diaphragm and a suction conduit from one or more ofl said 'outer Venturis connected to the chamber of said rnotorl on the opposite side ofy said' flexible diaphragm.

2'. Intacarbur'etor for internal combustion engines, the combination of a plurality of inlet conduits leading tov different cylinders ofy the engine, each conduit having respectively a` throttlevalve, a Venturi Qn the inner sideof said throttle valve, a Venturivonvthe outer side offsaid-j throttle valve and a fuel' injection port` in saidinner Venturi, a single meteringmeans for the fuelsupply, fuel' connections between saidjsingle metering means and each of said fuel injection ports,4s`uctio n motor means having two. suction chambers and having movable diaphragm means associated with said' chambers and operativelyconnected to said'metering means, a suction conduit'lfrom one o f said suction chambers connected to one or more of said innerVenturis and a second suctionconduit from the other o fsaid'suctionchambers connected to one or moreofl the said'4 outer Venturis.

3. In a carburetor for internal combustion engines, the Combination. of. a glurality of. inlet eonduits. leading. to-

different cylinders of the engine, each conduit having a throttle valve and a fuel injection port between said throttle valve and the engine, a single metering means for the fuel supply, fuel connections between said single metering means and each of said fuel injection ports, suction motor means having two suction chambers and having movable diaphragm means associated with said chambers and operatively connected to said metering means, a suction conduit from one of said suction chambers connected to one or more of said inlet conduits on the engine side of the throttle valve, and a second suction conduit from the other of said suction chambers connected to one or more of said inlet conduits on the inlet side of the throttle valve, said last mentioned chamber 6 connected on the inlet side of the throttle being also provided with a bleed hole for introducing atmospheric air at a predetermined rate.

References Cited in the le of this patent UNITED STATES PATENTS 

